U.S. patent number 4,819,790 [Application Number 07/063,487] was granted by the patent office on 1989-04-11 for leakproof endless belt conveyor.
This patent grant is currently assigned to M. L. Eakes Co.. Invention is credited to Jimmy L. Adcock.
United States Patent |
4,819,790 |
Adcock |
* April 11, 1989 |
Leakproof endless belt conveyor
Abstract
The side edges and return end of an endless belt conveyor are
sealed to prevent particulate material deposited thereon from
leaking off the sides and being lost, or worse, from working its
way beneath the belt, onto the slide pan, and into the pulleys and
end rollers. The front or discharge end in a preferred embodiment
is also provided with an air seal to prevent occurrence of the same
problems there. The top of the conveyor is covered with a hood.
Inventors: |
Adcock; Jimmy L. (Pleasant
Garden, NC) |
Assignee: |
M. L. Eakes Co. (Greensboro,
NC)
|
[*] Notice: |
The portion of the term of this patent
subsequent to June 23, 2004 has been disclaimed. |
Family
ID: |
26743464 |
Appl.
No.: |
07/063,487 |
Filed: |
June 17, 1987 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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561772 |
Dec 15, 1983 |
4674626 |
Jun 23, 1987 |
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Current U.S.
Class: |
198/811; 198/720;
198/836.1 |
Current CPC
Class: |
B65G
15/60 (20130101); B65G 2201/04 (20130101) |
Current International
Class: |
B65G
15/60 (20060101); B65G 015/60 () |
Field of
Search: |
;198/494,580,690.2,699,720,811,836,837,841,860.1,860.3,860.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Valenza; Joseph E.
Attorney, Agent or Firm: Rhodes; C. Robert Garmon; Judith E.
Doerr; Erwin
Parent Case Text
cl REFERENCE TO RELATED APPLICATIONS
This application is a continuation of my earlier and copending
application Ser. No. 561,772, filed Dec. 15, 1983, now U.S. Pat.
No. 4,674,626, issued June 23, 1987.
Claims
What is claimed is:
1. An endless belt conveyor for receiving and delivering
particulate matter deposited thereon toward a discharge end
comprising:
(a) a pair of spaced side walls extending the length of said
conveyor;
(b) a drive roller journalled in and extending between said side
walls at the discharge end of said conveyor and a return roller
journalled in and extending between said side walls at the rear end
of said conveyor;
(c) a bottom dust pan connecting the lower edges of said side walls
and extending beneath the area defined by said drive roller, said
return roller, and said side walls;
(d) an upper support pan extending between said side walls
generally parallel to said bottom dust pan at a level intermediate
the top and bottom of said side walls, said upper support pan
extending between said drive roller and said return roller and
comprising an air chamber formed by top and bottom panels and side
and end walls, perforations in said top panel, and means for
introducing a flow of air into said chamber which air escapes
through said perforations in said top panel;
(e) an endless belt extending around said drive roller and said
return roller, the upper flight of said belt resting on the top
panel of said support pan in the absence of said air flow but being
lifted to form an air slide conveyor in the presence of air, and
the lower flight of said belt being spaced above said dust pan,
said belt being narrower in width than the corresponding width of
said support pan and dust pan, whereby the opposite site side edges
of said belt are spaced from said side walls, said belt further
including at least one cleat extending transversely of said belt
and upstanding therefrom, the height of said cleat above the
surface of said belt being at least as great as the space between
said lower flight and dust pan whereby the cleat wipes the dust pan
clean as the lower flight passes thereby;
(f) a sealing block mounted on each side wall above the side edges
of said upper flight and extending the length of said upper flight,
the spacing of said sealing block from the top panel of said
support pan being greater than the thickness of said endless belt
so that upon introduction of said air flow the upper flight of said
belt is lifted until the lateral edges thereof engage the underside
of each of said sealing blocks to aid in formation of a side seal
and prevent passage of air and particulate matter therebetween;
and
(g) a selvage strip extending longitudinally of and attached to
said side walls at a point above said endless belt, said selvage
strip comprising an angular member extending downwardly and
inwardly from the inner surface of the adjacent side walls to a
termination point spaced above the side edges of said upper flight
and a horizontal member extending from said termination point to
said side wall, said sealing block being attached to the
undersurface of said horizontal member, whereby said selvage strip
provides an angular side wall to contain particulate material on
said endless belt as well as providing a support means for the
sealing block, the outer edge of said sealing block being spaced
from said side wall, and a longitudinal air channel formed between
said side wall, said sealing block, the undersurface of said
horizontal member, and the top surface of said support pan for
capturing some of the air escaping through the perforations in the
top panel of said support pan.
2. The endless belt conveyor according to claim 1 and further
including a sealing block between said dust pan and the lateral
edges of the lower flight of said endless belt, said sealing block
extending the length of said lower flight and being so arranged
with respect to said lower flight that the lateral edges of said
lower flight rest by gravity upon said sealing strip thereby
effectively forming a barrier tending to maintain the particulate
material on said dust pan rather than to allow it to escape off the
sides thereof.
3. The endless belt conveyor according to claim 2 and further
including end caps surrounding the lateral edges of said endless
belt as it moves around the discharge end of said conveyor
apparatus, said end cap including a sealing means for maintaining
said particulate material within the confines of the belt.
4. In a conveyor of the type wherein an endless belt having side or
lateral edges includes upper and lower flights extending between a
rear or feed end and a front or discharge end and wherein
particulate matter is deposited on and carried by the upper flight
toward the discharge end, discharged from the belt as the upper
belt reaches the discharge end and moves around an end roller, and
wherein a dust pan extends the length of and beneath the lower
flight of the belt conveyor, the improvement wherein said
particulate matter is prevented from leaking off said dust pan or
around the lateral edge of the lower flight and into the area
between the upper and lower flights, said improvement
comprising:
(a) cleat means carried by said endless belt conveyor for
periodically wiping said dust pan clean;
(b) lower sealing means extending along and adjacent each lateral
edge of said lower flight of said endless belt conveyor between the
side edges thereof and said dust pan for preventing collection of
said particulate matter from said dust pan on the top surface of
the lower flight of said endless belt which can work its way
between the flights and for preventing loss of particulate matter
through the side space between the lower flight and said dust
pan;
(c) said lower sealing means including a sealing block mounted on
said dust pan adjacent along each side edge thereof, and separating
the dust pan from the lateral edges of the lower flight of said
endless belt, each of said sealing blocks extending the length of
said lower flight, the distance between said sealing blocks being
less than the width of said belt conveyor, so that the lateral
edges of said lower flight of said belt conveyor rests by gravity
upon the upper surface of said sealing blocks thereby effectively
forming a chamber between the dust pan, lower flight, and the
sealing blocks tending to maintain the particulate material on said
dust pan rather than to allow it to escape across the sides
thereof;
(d) said cleat means extending outwardly from the surface of said
belt a distance at least as great as the space between said lower
flight and said dust pan whereby the cleat wipes the dust pan clean
as the lower flight passes thereby.
5. The conveyor of claim 4 and further including an upper sealing
means extending along each lateral edge of said upper flight of
said endless belt conveyor for preventing escape of particulate
matter off the side of the upper flight of said belt conveyor.
6. The improvement for endless belt conveyors according to claim 5
wherein said upper sealing means comprises a sealing block and
means for introducing an air flow beneath the upper flight of said
endless belt to urge the edges thereof into sealing engagement with
said upper sealing block to prevent passage of particulate matter
therebetween.
7. The improvement according to claim 4 and further including a
rear end sealing means associated with the edges of said endless
belt conveyor at the rear end thereof to prevent loss of
particulate matter along the sides of the belt conveyor as it
passes around the rear end roller.
8. The improvement according to claim 7 and further including a
front end sealing means at said discharge end of said endless belt
conveyor for pneumatically urging particulate matter toward the
center of said belt as it passes around the front end roller.
Description
BACKGROUND OF THE PRESENT INVENTION
This application relates to endless belt conveyors of the type in
which the upper and lower flight of an endless belt extend around
and between a front end drive roller and a rear end return roller.
Such types of endless belt conveyors are used to convey material
from one point of an industrial or manufacturing facility to
another, sometimes directly, and sometimes by utilizing a plurality
of such conveyors in sequence in which material is deposited onto
one end (feed end) of a conveyor and delivered to the other or
discharge end from whence it is discharged onto another conveyor
which may be running in an opposite direction or in the same
direction. Such conveyors may be positioned on the floor and easily
accessible, or they may be positioned up near the ceiling of such
manufacturing or industrial facilities to provide more operating
space therebelow. Sometimes such conveyors are used to carry
discrete items of large size thereon, in which case the features of
the present invention are not as relevant. In other cases, however,
such conveyors are used to carry particulate material such as
tobacco, fibers, grain, sand, and the like thereon. Endless belt
conveyors may includes a flat belt; they may have side walls with
slanted selvage strips therealong to provide a trough for the
material; or the bed of the conveyor itself and the belt may be
curved to provide more of a trough-like effect. It is in
conjunction with all of these types of conveyors, which carry
particulate material, that the present invention is concerned.
In such conveyors for carrying particulate material, several
problems may occur. First, depending upon the particulate material,
considerable amounts thereof may be lost during the conveying in
various ways. First of all, material may be lost at the transfer
point from one conveyor to another by the material either being
spilled off the sides at the transfer point, or becoming airborne
as would be the case in very small powder-like material, such as
fibers, or tobacco. Material is also lost at the discharge end of a
conveyor where the belt conveyor bends around the drive roller, and
the curve that has been built into the conveyor must return to a
flat configuration. At this point, it is difficult to constrain the
material within the confines of the belt and it is sometimes lost
over the edges of the belt as it progresses around the discharge
pulleys or rollers. A significant area where particulate material
is lost is across the lateral edges of the upper flight of the belt
conveyor if there are no side walls thereon. Generally this can be
corrected to some extent by providing side walls. Material is also
lost that clings to the belt conveyor as it becomes the lower
flight returning beneath the upper flight. Often the material that
clings to the belt will become deposited either on the floor
beneath the conveyor, or on some type of dust pan therebeneath
which must be periodically emptied. Finally, material is also lost
as the belt moves around the rear or return end of the conveyor.
Here, in cases in which there is a dust pan beneath the lower
flight, there will be some type of cleat or wiper attached to the
conveyor at spaced points to wipe the pan clean and bring it back
around the return end of the conveyor to the upper flight. In such
cases at the rear end, material is often lost off the edges of the
return bight of the conveyor.
A separate problem which occurs, other than lost material, is the
damage caused by particulate material which works its way between
the flights of the belt conveyor, between the conveyor and its
support pans, or between the conveyor and the return rollers. Such
material builds up, becomes deposited in the rollers, and
eventually will cause damage unless the conveyor is periodically
stopped, torn down by a machinist and either cleaned or repaired.
This obviously results in expensive down time and maintenance.
SUMMARY OF THE PRESENT INVENTION
The present invention, on the other hand, is directed to a solution
for the above problems which is accomplished by providing an
effective edge seal for the belt conveyor, not only along the upper
flight thereof, but along the lower flight, and around the drive
roller and return roller. In addition, the conveyor of the present
invention is provided with a cover or hood to prevent loss of
material which becomes airborne. By providing the cover, not only
can material be maintained within prescribed confines, but since
there is an enclosed atmosphere, that atmosphere can be treated by
the introduction of moisture or like to provide a humidity control,
which may be very important in the process of some particulate
materials such as tobacco and textile fibers.
There are four basic areas of the conveyor with which to be
concerned: (1) the side edges of the upper flight of the belt
conveyor; (2) the side edges of the lower flight of the belt
conveyor; (3) the side edges of the belt conveyor as it moves
around the return end of the roller; and (4) the side edges of the
belt conveyor as it moves around the discharge end roller. In the
broadest sense, seals for these areas may be effected to some
extent merely by providing a sealing block that is formed
appropriately and positioned on the side walls of the framework of
the conveyor at such points as to provide a friction type
engagement of the side edges of the belt all the way around its
circumference. This is a viable approach within the scope of the
present invention; however, there are certain further advantages
which may be achieved by utilizing other features of the conveyor
which are present.
For example, air slide conveyors have become available more in
recent years. Air slide conveyors offer the advantage that the
normal friction which occurs between the conveyor belt and its
support pan is minimized. As a result, less energy is used in
driving the belt, and less wear is realized on the belt with the
result that less maintenance is required. By incorporating the seal
concept of the present invention in an air slide conveyor, the air
which impinges against the underneath side of the belt may be
utilized to help form the side and end seals in the following
manner. As air impinges on the underneath side of the belt, it
lifts the side edges of the belt into engagement with side sealing
blocks to effect the side seal discussed hereinabove. The air is
then channeled off the sides, collected into a longitudinal
channel, and conducted to the discharge end roller where it is
allowed to discharge inwardly toward the axial center of the
conveyor belt. This discharged air blows the particulate material
back toward the center of the belt and prevents escape of the
material through the sides thereof. The slight pressure of the side
edges of the belt against the side sealing blocks along the
longitudinal extent of the upper flight thereby provides sufficient
seal to prevent inadvertent discharge of the particulate material
off the sides of the belt, and yet does not cause undue wear or
drag on the belt. Also, rather than pressing sealing blocks against
the lower flight, the lower flight of the belt is allowed to drop
by gravity onto the sealing blocks to provide a slight pressure
thereagainst, which is sufficient to prevent inadvertent loss of
material across the side edges of the belt as it returns underneath
the conveyor.
One or more cleats are provided on the endless belt to continuously
wipe the dust pan beneath the conveyor, thereby preventing buildup
of fine dust thereunder. As the belt then returns over the return
roll, a return roller cap includes a sealing block which provides
slight pressure against the edge of the belt conveyor to prevent
loss of material thereunder.
It is therefore an object of the present invention to provide an
improved endless belt conveyor which prevents leakage of
particulate matter cross the edges thereof.
Another object of the present invention is to provide an improved
endless belt conveyor of the type described in which the leakage is
prevented by sealing the side edges completely around the
circumference of the belt conveyor.
Yet another object of the present invention is to provide a
leakproof endless belt conveyor which utilizes an existing supply
of air on the conveyor to effect the seal along the upper flight
side edges and drive roll side edges.
Other objects and a fuller understanding of the invention will
become apparent from reading the following detailed description of
a preferred embodiment along with the accompanying drawings in
which:
FIG. 1 is a perspective view looking at the discharge end of the
endless belt conveyor according to the present invention;
FIG. 2 is a sectional view taken substantially along lines 2--2 in
FIG. 1;
FIG. 3 is an enlarged perspective view, with parts broken away,
illustrating a portion of the discharge end of the conveyor;
FIG. 3a is a perspective view illustrating the inside of a
discharge end cap removed from the conveyor;
FIG. 4 is a perspective view, with parts broken away, illustrating
the rear or feed end of the conveyor according to the present
invention;
FIG. 5 is a perspective view illustrating the rear end cap removed
from the conveyor of the present invention; and
FIG. 6 is a perspective view of one support pan section
illustrating the top, end, and one side.
cl DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Turning now to FIG. 1, there is best illustrated an overall view of
the endless belt conveyor 10 of the present invention which is
supported on any type of conventional type of framework 12. The
conveyor apparatus 10 includes an endless belt conveyor 14 having a
rear or feed end 16 and discharge end 18. Particulate material is
fed from a hopper or from the discharge end of a preceding conveyor
through a feed chute 20 onto the feed end 16 of conveyor 14. It
should be pointed out that in some cases the feed chute 20 may be
eliminated and the particulate matter be fed directly from the
discharge end of one conveyor (not shown) onto the feed portion of
a subsequent conveyor.
A fan 22 is mounted in any convenient location and includes a hose
24 and input nozzle 26 for directing a positive flow of air into
the interior of the conveyor apparatus 10 as will be described
hereinafter. A drive motor 28 is mounted on a suitable support
bracket 29 above the discharge end 18 of the conveyor apparatus for
supplying the drive force necessary to turn drive roller 38. In
this regard output shaft 30 from drive motor 28 includes an upper
pulley 32 attached to the end thereof, and a drive chain 34
connects the upper pulley 32 with the lower pulley 36. In turn, the
lower pulley is secured to the end of drive roller 38, whereby
operation of the drive motor causes the drive roller to rotate
carrying the endless belt 14 in its conveying path. A plurality of
cover sections 40 extend across the upper edges of the side walls
of the conveyor apparatus and attach to cover brackets 42. The
covers are preferably of a transparent plexiglas material,
substantially flat, however, are bent into the domed shape
illustrated in FIG. 1.
Turning now to FIG. 2, there is illustrated a cross-sectional view
of the conveyor apparatus 10. A pair of side walls 44,46 extend in
sections longitudinally of the length of the conveyor apparatus 10.
A dust pan 48 connects the lower edges of side walls 44,46 and
catch any particulate material which falls from the lower flight 74
of the endless belt 14. A support pan 50 extends between side walls
44,46 at a point approximately intermediate the height thereof.
Support pan 50 includes a perforated upper panel 52, a lower panel
54, side panels 56,58, and end walls 60. The support pan 50 is
formed in a plurality of sections approximately ten feet in length.
Further, each section is assembled by means of brackets 80, which
are positioned at each end of each pan section. The brackets from
one pan thus abut the adjacent brackets from the other pan, and
bolts (not shown) extend through openings 81 in the bracket to
secure the pans together. Each end wall 60 of the pans 50 include a
plurality of openings 62 therein, so that when the pans are
assembled, there is a continuous air communications from one end of
the conveyor to the other through the pan. The pan construction can
be further seen in FIG. 6. Each opening 60 includes a rubber or
polymeric grommet 65 (FIG. 6) therearound, so that when two
adjacent pans are abutted, the grommets of one pan engage the
grommets of another and provide a seal to prevent leakage of air
therearound.
A selvage strip 63 extends along the inner surface of side walls
44,46 longitudinally thereof. The selvage strip 63 is triangular
shaped and includes an angled member 64 and a horizontal member 66.
Angled member 64 is secured to the side wall 44,46 at a point near
the upper edge thereof and extends inwardly and downwardly
therefrom to a point 65 which is spaced above support pan 50. The
horizontal member 66 extends from the termination point 65 of angle
member 64 horizontally outwardly toward the side wall and is
connected thereto. A sealing block 70 is attached to the
undersurface of horizontal member 66, however, terminates at a
point 71 spaced from side walls 44,46 for reasons to be hereinafter
described.
In the arrangement illustrated in FIG. 2, the upper flight 72 of
the endless belt 14 then lies between the sealing block 70 and the
upper panel 52 of support pan 50. The lateral edges of upper flight
72 extend to a point approximately one inch from the side walls
44,46. In the normal position with no air introduced through inlet
nozzle 26, the upper flight 72 rests on the upper panel 52 of the
support pan 50. However, when the fan 22 is activated upon
activation of the motor 28, and air is introduced into the interior
of support pan 50 through nozzle 26, the air passing through
perforations 76 causes the upper flight 72 to lift into sealing
engagement with sealing block 70. Obviously, there must be a side
opening in one of the pan sections 50 and through side wall 46 to
allow introduction of air thereinto. Otherwise, the remaining
support pan sections do not need side openings, because once the
air is introduced into one of the support pans, it is communicated
with the other support pans through the openings 62.
The air that impinges against and lifts the upper flight 72 of the
endless belt, moves outwardly into the longitudinal channel 78
which extends lengthwise of the conveyor apparatus and is formed by
the outer edge of sealing block 70, the upper panel 52 of support
pan 50, the inner surface of walls 44,46, and the under surface of
the horizontal member 66 of selvage strip 63. The purpose of this
air conduit will be discussed hereinafter.
The lower sealing blocks 68 extend longitudinally of the conveyor
apparatus 10 alongside side walls 44,46, and are attached to and
rest on dust pan 48. The lateral edges of lower flight 74 then rest
upon sealing blocks 68 as the lower flight returns beneath the
conveyor. As the lower flight 74 returns, one or more cleats 73
attached to the surface of the endless belt 14 wipe the pan 48
clean. Obviously, the height of cleat 73 must be at least equal to
or greater than the distance between lower flight 74 and dust pan
48 in order to obtain the required wiping action.
The sealing action at the discharge end is best illustrated in
FIGS. 3 and 3a. Toward this end, there is provided an end cap 82
which basically extends the seal around the end of the discharge
roller to seal the lateral edges of the endless belt 14 as it
circumnavigates the end rollers. Cap 82 includes an arcuate shaped
metal cover 84 which is attached to the adjacent side wall 44,46 or
to the selvage strip 63 in any conventional manner. Inside the
metal cover 84 is an arcuate shaped sealing block 86 having the
same outer radius of curvature as that of the metal cover 84.
Looking at FIG. 3a, it can be seen that block 86 is not as wide as
metal cover 84, and therefore there is a channel 88 remaining
between the block 86 and side walls 44. The sealing block 86 is
also arcuate shaped, so that when assembled, channel 88 is actually
an extension of the longitudinal channel 78 illustrated in FIG. 2.
Thus, when the air is introduced through nozzle 26 into the support
pans 50, as it flows into channel 78, the air will flow down into
channel 88. The inner curvature of sealing block 86 is such that
there is a slight gap 90 between sealing block 86 and the return
bight of the discharge end 18 of the endless belt 14. Thus, there
will be a flow of air through the gap 90 which will tend to force
any particulate material near the edge of belt 14 back toward the
central axis thereof. This air flow thus acts as an air seal to
keep particulate material from working its way through the slot 90
at the discharge end of the conveyor.
Turning now to the rear end 16 of the conveyor apparatus 10, there
is illustrated in FIGS. 4 and 5 the sealing means for preventing
particulate matter from escaping from the endless belt 14 at that
point. In this regard, a shield 92 encircles the endless belt 14 as
it moves around the rare end roller. As can be seen in FIG. 5 a
generally U-shaped sealing block 94 is attached to the inner
surface of shield 92, and when assembled, provides a slight
frictional engagement with the lateral edges of belt 14. This
effectively forms a seal and maintains the particulate material on
the belt 14 as it moves around the rear or feed end of the conveyor
apparatus. The sealing block 94 has a pair of legs 96,98 which
engage correspondingly shaped portions of sealing blocks 68 and 70
of the rear end conveyor section. The air from channel 78 which
flows rearwardly of the conveyor merely escapes this point to
prevent a buildup of air. While a gravitational type air seal has
been shown, it is obvious that an air seal could be provided for
the lower flight also by expanding the depth of support pan 50 and
providing perforations in the lower panel thereof. Air would then
impinge against the lower flight and force it against sealing
blocks 68.
Looking now at FIG. 6, there is illustrated a portion of one of the
support pans which better illustrates the perforations 76 in the
upper surface thereof and the openings 62 in the end walls with the
grommets 65 therearound. It should be pointed out here that should
the openings 62 not be sufficient to provide a good flow of air
longitudinally of the conveyor, the openings 62 can be replaced
with a larger slot or plurality of slots.
Finally, should the particulate material being processed need a
controlled atmosphere, such as humidity control, this can be easily
accomplished by introducing the air with the proper moisture
content through nozzle 26 to the support pans 50. The only
difference in the construction of the conveyor 10 would be that
when the air is introduced into side channels 78, there are
perforations 67, 69 in the horizontal member 66 and angular member
64, respectively, of the selvage strip which allows communication
for the humidified air to be introduced into the conveying chamber
which extends between side walls 44,46.
While a preferred embodiment of the invention has been described in
detail hereinabove, it is obvious that various changes and
modifications might be made without departing from the scope of the
invention which is set forth in the accompanying claims.
* * * * *